1 files changed, 115 insertions, 0 deletions
diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..bf2c762
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,115 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <dirent.h>
+#include <limits.h>
+#include <unistd.h>
+
+/* get insert-before offset of first argument if any, argv end if none, or -1
+ * if wd already defined */
+int get_wd_off(int argc, char *argv[])
+{
+	int i;
+
+	for (i = 0; i < argc; i++) {
+		if (strcmp("--working-directory", argv[i]) == 0)
+			return -1;
+		if (argv[i][0] == '-')
+			break;
+	}
+
+	return i;
+}
+
+/* walk through /proc looking for alacritty cmdline */
+bool walk_proc(void)
+{
+	struct dirent *de;
+	DIR *d = opendir("/proc");
+	FILE *f;
+	char path[PATH_MAX], cmd[PATH_MAX];
+
+	if (d == NULL)
+		abort();
+
+	while ((de = readdir(d)) != NULL) {
+		path[0] = '\0';
+		strcat(path, "/proc/");
+		strcat(path, de->d_name);
+		strcat(path, "/cmdline");
+
+		f = fopen(path, "r");
+
+		if (f == NULL)
+			continue;
+
+		fscanf(f, "%s", cmd);
+
+		if (strstr(cmd, "alacritty") != NULL) {
+			fclose(f);
+			closedir(d);
+			return true;
+		}
+
+		fclose(f);
+	}
+
+	closedir(d);
+
+	return false;
+}
+
+int main(int argc, char *argv[])
+{
+	/* two for --working-directory and cwd, two for msg and create-window, one
+	 * for NULL */
+	char *argvnew[argc + 5];
+	char wd_arg_str[] = "--working-directory";
+	char cwd[PATH_MAX];
+
+	char alacritty[] = "alacritty";
+
+	char *msg_create_window[] = {"msg", "create-window"};
+
+	int i;
+	int wd_off = get_wd_off(argc, argv);
+
+	argvnew[0] = alacritty;
+
+	/* insert --working-directory cwd if not already extant */
+	if (wd_off == -1) {
+		for (i = 1; i < argc; i++) {
+			argvnew[i] = argv[i];
+		}
+
+		argvnew[i] = NULL;
+	} else {
+		getcwd(cwd, sizeof(cwd));
+
+		for (i = 1; i < wd_off; i++)
+			argvnew[i] = argv[i];
+
+		argvnew[i] = wd_arg_str;
+		argvnew[i + 1] = cwd;
+		i += 2;
+
+		for (; i < argc + 2; i++)
+			argvnew[i] = argv[i - 2];
+
+		argvnew[i] = NULL;
+	}
+
+	/* check if alacritty is running and, if so, insert msg create-window */
+	if ( (argc < 2 || strcmp("msg", argv[1]) != 0) && walk_proc()) {
+		/* shunt args up two to make room */
+		for (i = argc + 4; i > 2; i--)
+			argvnew[i] = argvnew[i - 2];
+
+		argvnew[1] = msg_create_window[0];
+		argvnew[2] = msg_create_window[1];
+	}
+
+	execv("/bin/alacritty", argvnew);
+}